Yellow stripes on the leaves of light green corn plants could indicate a sulfur deficiency, a South Dakota State University specialist said.
SDSU Extension Soils Specialist Jim Gerwing says cornfields in which entire plants or at least many leaves on a plant are striped very likely indicates sulfur deficiency. Yellow stripes on light green plants are common.
The sulfur deficiency appears to be most pronounced on sandy, coarse-textured soils that are low in organic matter. Gerwing says it's also much more pronounced in no-till systems, since those soils stay colder and the release of sulfur from organic material is slower.
Yellowing that isn't accompanied by striping may be nitrogen deficiency, Gerwing says, especially in areas that have had high rainfall. Some producers may see a combination of both nitrogen deficiency and sulfur deficiency, Gerwing says.
Zinc deficiency also causes striping, but only on parts of the leaf, not the whole leaf, and the plants don't get as yellow as with sulfur deficiency.
Gerwing says sulfur deficiencies are showing up more frequently in South Dakota in recent years because soils have been farmed longer, which means organic matter levels are going down. The shift toward more no-till farming is also a factor, since no-till farming slows down the breakdown of the organic matter, slowing the release of sulfur.
Farmers can apply sulfur if they recognize a sulfur deficiency, Gerwing says.
"We need to use a sulfate form of sulfur. Probably our only option is ammonium sulfate, which is 21-0-0-24 as a grade. About 100 lbs/acre of the material, which will supply about 24 or 25 lbs. of sulfur, should do the trick. A person can just broadcast that over the surface, and rainfall will move it right into soil."
Because ammonium sulfate fertilizer is 21% nitrogen, it also gives crops an added shot of nitrogen, Gerwing says. Producers farming light, coarse-textured soils that have seen heavy rains may need to use more nitrogen.
Gerwing recommends producers first test to find out which nutrients are needed.